Locking device



Nov. 16 1926.

S. B. REDFIELD LOCKING DEVICE Filed March 31, 1926 2 Sheets-Sheet 1 h 'INVENTOR: axaowdenB afi eld BY 7/ Y J I v H/6 AITRNEY Patented Nov. 16, 1926.

UNITED STATES 1,606,844 {PATENT OFFICE.

SNOWDEN B. REDFIELD, OF EASTON, PENNSYLVANIA, ASSIGNOR T0 INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

LOCKING DEVICE.

Application filed March 31, 1926. Serial No. 98,823.

This invention relates to looking devices, but more particularly to a locking device for forming a connection between two members, such as pistons and the like, and in which the members are intended to be arranged substantially coaxially with respect to each other.

The present invention is particularly applicable to compressors or engines of the type in which dilierential pistons are employed and aims to permit relative transverse movement between. two pistons, so that the pistons may adjust themselvesin their respective cylinders when the diameters of the pistons change due to variations in temperature and other causes of axial. misalignment.

Another object is to prevent relative longitudinal movement between the various portions which comprise the piston.

Other objects will be in part obvious and in part pointed out hereinafter.

The invention consists of the combination of elements and arrangement of parts substantially as hereinafter described and more particularly pointed out in the appended claims and illustrated in the accompanying drawings, in which Figure 1 is an elevation in section of a portion of an air compressor having a differential piston and in which the portions comprising the piston are held together by a locking device constructed in accordance with the practice of the invention,

Figure 2 is an enlarged detail view partly in section illustrating more clearly the inanner in which the pistons are locked together,

Figure 3 is a perspective view of the piston rod nut,

Figure 4 is a perspective view of the piston rod lock nut,

Figure 5 is a perspective View showing a modification of a piston rod lock nut,

Figure 6 is a view in section taken through Figure 5 on the line 66 looking in the di rection of the arrows,

Figure 7 is a perspective view of a modified form of piston rod lock nut,

Figure Sis a view in section taken through Figure 7 on the line 8-8 looking in the direction of the arrows, V

Figure 9 is a perspective view of a 1nodifiedform of piston rod nut,

Figure 10 is 'a view in section taken through Figure 9 on the line 1010 looking in the directlon of the arrows,

F lgure 11 is a perspective view illustrating another modification of the piston rod nut, and

Figure 12 is a view in section taken through Figure 11 on the line 1212 looking in the direction of the arrows.

Referring to the drawings, the invention is shown embodied in a compressor designatedgenerally by A and having a cylinder B in which is arranged a reciprocatory piston C. The piston C is of the double acting type and divides the cylinder B into a low pressure chamber D and an intermediate pressure chamber E. In the present instance the piston C carries at its rearward end a skirt F which cooperates slidably with a bore G formed in the cylinder B for, guiding the piston C and also to form a head for the intermediate pressure chamber E.

Secured to the end of the cylinder B is a cylinder H which in this instance comprises the high pressure c linder of the unit and carries at its forwar end a head J in which are arranged suitable inletand exhaustvalv'es K and L. In like manner, inlet valves K and exhaust valves L are provided for the low pressure and intermediate pressure chambers. In the drawings only one inlet valve and one exhaust valve is shown for each of the cylinder chambers, but it is to be understood thatthi's'showing is merely made for illustrative purposes and that any suitable number of valves of either type may be provided for the various cylinder'chambera The cylinder chambers are of course adapted to be connected to each other by suitable conduits (not shown) as is customary in machines of this type, but

since the parts so far described, other than the piston C, form no part of the present invention, further description thereof is considered unnecessary. I

In accordance with the practice of the invention, a recess 0 is formed in the low pressure end of the pistorrC and into the bottom of this recess is arranged a wearing plate P' which forms a seat for a flange Q, carried by a piston rod R. The piston rod R acts as a support for a piston s which reciprocates in the cylinder H and is'held against longitudinal movement on thepiston rod R by a suitable nut T screwed on/the outer end of the said piston rod. Formed between the flange Q, and the piston rod R is a cylindrical portion U of somewhat greater diam,

eter than the piston rod R but of smaller diameter than the flange Q. and about which may be arranged a piston rod nut V threaded on its perimetric surface to cooperate with a threaded portion W at the outer end of the recess (a). The piston rod nut V is adapted to seat on a shoulder X formed in the recess and cooperates with an end of the flange Q for preventing longitudinal movement of the flange in therece'ss O. The

bore Y in thepiston rod nut V is prete "ably of somewhat larger diameter than the portlons U oi the piston rod R-so that the rod R is free to move transversely within limits the reciprocatory element of the machine,

A'ltliough the flange Q- of the piston rod R is illustrated as beinginline to line contact with the wearing plate P, it isto be noted that sutiicient clearance isallowed between these members to permit of tree. transverse movement of the flange Q, in the recess 0. In order that relative movement of the piston and therrod R upon which it .is mounted may be prevented, a pin Z or other 7 similar locking device may beinserted into the portion U of the rod to cooperate with a slot 7) formed in the end of the piston S. This forms a simple means .for preventing when assembling these parts.

Frequently in devices .of this character rotation'between the piston and the rod considerabledifficulty is experienced in prerenting unloosening of the piston rod nut or other equivalent means used for holding the pistons together. tendency in the present instance a lock nut a To overcome this of substantially the same diameter as the piston rod nut V is screwed into the threaded recess W to'bear at its inner portion rod nut V and the lock nut '0.

againsta fiat portion d formed on the piston rod nut V. The flat portion (l comprises only a relatively small area at one end of the ,7 piston rodnut V and in this instance the piston .rod nut V is tapered from the flat portion'cZ in the direction of the threaded portion of the nut so that when the lock nut 0 is screwed in position in the recess W only a small contact will exist between the piston To the end that the lock nut -0 may be somewhat distorted within the threaded recess for the purpose of preventing accipurposes.

dental unscrewing of the lock nut, a series of slots 6 arelcut in an end face of the lock nut a The slots 0 may be of any suitable number, four being shown for illustrative Cutting the slots ,6 in the lock nut c has the eliect of reducing the section of the lock nut so that when the pressure is applied to the lock nut i'or screwing it into the recess W, the threaded or outer portion of the nut is drawn out of the plane of the central portion of the lock nut, thus producing a binding eil'ectbet-ween the threads of the lock nut and those oi the threaded recess iv. The slots c'also provide a coir-cement means for the insertion of a wrench or other suitable instrument whereby the loci; nut

may be n'ianipulated. The piston rod nut Y is also provided with suitable slots torthe reception of a wrench for screwing the said I nut nto and out of the recess VF.

In assembling the pistons, the wearing plate P may be seated in the bottom of the recess (l. The piston rod B may then be placed in the recess and the piston rod nut Vfscrewed firmly against the shoulder X. llhereatterthe lock nut 0' may be screwed into the recess against the hat portion (Z of the piston rod nut V. Continued turning V oi' the lock nut c inthe direction required for turning it into the recess will draw the outer portion of the lock nut in the direction ofthe nut V and cause said lock nut to bind in the manner described, With the nuts V mounted on the piston rod B so that the slot 6 in the piston S engages the pin- Z.

' The advantages of this invention reside chiefly in the fact that two members, such as the plstonsC and S, may be securely locked together and that the. securing, means thus employed will at alltimes prevent any relative longitudinal movement between the pistons, while at the same timelpermitting relative transverse adjustment to compensate for any slight eccentricity of thefcylinders which may occur during the machining of the parts; or tor any unequal expansion or contraction of the walls of the Several cylinders during the operation the compresson V Referring now to Figuresb and 6, a lock nut 9 1s shown having VL -shaped slots ]i which divideithe lock nut into segments con nected small ribs j. The ribs j serve to render the mu: 9 flexibleso that when the nut is drawn. firmly against the piston rod nut V, the threaded portion of the lock nut y will be drawn out of alignment with the central portion of the lock nut and thus hold said lock nut firmly in. placed position. A further modification is illustrated in and c in position, the piston in may be Ill) Figures '7 and 8 in which longitudinal slots 70 are cut through the threaded portion of the lock nut 0 and an annular groove p is cut in one face of the lock nut, preferably in line with the inner walls Q of the slots 70.

A modified form of piston rod nut is illust'ated in Figures 9 and 10. In this instance one end of the piston rod nut 7* is provided with tapered surfaces 8 and 25 which converge to form a prominence it against which the lock nut may be forced tor the purpose of springing the lock nut to cause it to bind in the threaded recess W.

Figures 11 and 12 show another form of piston rod nut in which one face of the piston rod nut '21 is spherical as at w. By thus forming the spherical face 20 on the nut, a single line of contact between the nut to and the lock nut will be assured, irrespective of any distortion which may take place in the lock nut.

It is to be understood that I do not wish to limit the invention to the precise showing in the drawings, but that the invention may be further modified in various particulars without departing from the spirit of the invention or the scope of the claims.

I claim:

1. In combination with a. pair of coaxial members, of a flange carried by one of the members, a recess in the other member to receive the flange, said recess having a threaded portion, a piston rod nut in the threaded portion cooperating with the flange to prevent relative longitudinal movement between the members, and means screwed into the threaded portion for locking the piston rod nut in position, said means being flexible to permit its outer portion to be drawn out of the plane of its central portion.

2. In combination with a pair of coaxial members, of a flange carried by one of the members, a recess in the other member to receive the flange, said recess having a threaded portion, a piston rod nut in the threaded portion cooperating with the flange to prevent relative longitudinal movement between the members, and a lock nutscrewed into the threaded portion of the recess to bear against the end of the piston rod nut for preventing unscrewing of the said piston rod nut, said lock nut having reduced portions to render it flexible and permit its outer portion to be drawn out of alignment with respect to its central portion.

3. In combination with a pair of coaxial members, of a flange carried by one of the members, a recess in the other member to receive the flange, said recess having a threaded portion, a piston rod nut in the threaded portion cooperating with the flange to prevent relative longitudinal movement between the members, a flexible lock nut screwed into the threaded portion of the recess for preventing unscrewing of the said piston rod nut, and a shoulder on the piston rod nut bearing against the lock nut to dis tort the lock nut thus causing the threads of the lock nut to bind on the threads of the recess for locking the lock nut against accidental removal.

4-. In combination with a pairot cylindrical members, of a rod insertable into one of the members, a flange on one end of the rod, a. recess in the other member to receive the flange and permit transverse movement of the flange, said recess having a threaded portion, a piston rod nut screwed into the threaded portion to cooperate with the flange for preventing longitudinal movement of V the flange in the recess, a projection on the piston rod nut, and a lock nut screwed into the threaded portion to seat against the projection for preventing unscrewing of the said piston rod nut, said lock nut having slots to permit distortion of the lock nut for locking said lock nut against accidental removal.

5. In combination with a pair of cylindrical members, of a rod insertable into one of the members, a flange on one end of the rod, a recess in the other member to receive the flange and permit transverse movement of the flange, said recess having a threaded portion, a shoulder in the recess, a piston rod nut screwed into the threaded portion to seat on the shoulder for preventing longitudinal movement of the flange in the recess, a projection on the outer end of the piston rod nut, and an externally threaded lock nut screwed into the threaded portion to bear against the projection for holding the piston rod nut against the shoulder, said lock nut having slots in one face to permit the externally threaded portion to be drawn out of the plane of the central portion of the lock nut for preventing unscrewing of the lock nut.

In testimony whereof I have signed this specification.

SNOWDEN B. REDFIELD.

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